What does it mean that motorcycles have double throttle lines?

Double throttle lines: one throttle line works when refueling and the other throttle line works when returning to throttle, so as to avoid the danger of high-speed overspeed of the engine when the carburetor does not return to throttle. These two lines lead to the throttle handle on the right side of the handlebar, and the top one is the throttle line, which is responsible for controlling the throttle and the oil needle, that is, controlling the throttle.

Extended information The traditional cable accelerator has one end connected to the accelerator pedal and the other end connected to the accelerator through a steel wire, and its transmission ratio is 1: 1, which means that the throttle opening is the same as how much we step on it with our feet, but in many cases, the throttle should not be opened at such a large angle, so the throttle opening at this time is not necessarily the most scientific. Although this method is direct, its control accuracy is poor.

Reference throttle line _ Baidu Encyclopedia